scholarly journals Investigation of the Charge Behavior of PAA Copolymers by Means of Polyelectrolyte Titration

2017 ◽  
Author(s):  
Simona Schwarz ◽  
Christine Steinbach ◽  
Dana Schwarz ◽  
Gudrun Petzold ◽  
Evgenia Romanova ◽  
...  
Keyword(s):  
Polyelectrolyte Titration

Complex formation of modified chitosan and carboxymethyl cellulose and its effect on paper properties

TAPPI Journal ◽  
2009 ◽  
Vol 8 (6) ◽  
pp. 29-35 ◽  
Author(s):  
PEDRAM FATEHI ◽  
LIYING QIAN ◽  
RATTANA KITITERAKUN ◽  
THIRASAK RIRKSOMBOON ◽  
HUINING XIAO
Keyword(s):  
Carboxymethyl Cellulose ◽  
Polymer System ◽  
Layer By Layer ◽  
Paper Strength ◽  
Anionic Polymer ◽  
Paper Properties ◽  
Modified Chitosan ◽  
Layer By Layer Assembly ◽  
Polyelectrolyte Titration ◽  
Layer Assembly

The application of an oppositely charged dual polymer system is a promising approach to enhance paper strength. In this work, modified chitosan (MCN), a cationic polymer, and carboxymethyl cellulose (CMC), an anionic polymer, were used sequentially to improve paper strength. The adsorption of MCN on cellulose fibers was analyzed via polyelectrolyte titration. The formation of MCN/CMC complex in water and the deposition of this complex on silicon wafers were investigated by means of atomic force microscope and quasi-elastic light scattering techniques. The results showed that paper strength was enhanced slightly with a layer-by-layer assembly of the polymers. However, if the washing stage, which was required for layer-by-layer assembly, was eliminated, the MCN/CMC complex was deposited on fibers more efficiently, and the paper strength was improved more significantly. The significant improvement was attributed to the extra development of fiber bonding, confirmed further by scanning electron microscope observation of the bonding area of fibers treated with or without washing. However, the brightness of papers was somewhat decreased by the deposition of the complex on fibers. Higher paper strength also was achieved using rapid drying rather than air drying.

On the Indirect Polyelectrolyte Titration of Cellulosic Fibers. Conditions for Charge Stoichiometry and Comparison with ESCA

Langmuir ◽  
2006 ◽  
Vol 22 (2) ◽  
pp. 824-830 ◽  
Author(s):  
A. Elisabet Horvath ◽  
Tom Lindström ◽  
Janne Laine
Keyword(s):  
Cellulosic Fibers ◽  
Polyelectrolyte Titration

Colloidal dynamics of soil clay under the effect of fine-sized biochars: Implication for biochar amendment towards preventing clay loss and soil erosion

2020 ◽  
Author(s):  
Nga T. Mai ◽  
Nga T. T. Pham ◽  
Anh T. Q. Nguyen ◽  
Anh T. N. Nguyen ◽  
Anh M. Nguyen ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Surface Charge ◽  
Clay Fraction ◽  
Test Tube ◽  
Soil Clays ◽  
Soil Clay ◽  
Ph Range ◽  
Polyelectrolyte Titration ◽  
Repulsive Forces ◽  
Biochar Amendment

<p>In soils clay loss by leaching and surface runoff is one of the initial steps increasing the risk of erosion. Here we set out to determine the effect of fine-sized biochar amendment on colloidal dynamics of soil clay, with the aim of answering whether biochar addition enhances or curbs soil erosion. Fine-sized biochar samples were prepared from fern Dicranopteris linearis’s biomass under non-biochar-oriented pyrolysis (open heating) and biochar-oriented pyrolysis (N<sub>2</sub>-supported heating) over a temperature range from 400 to 900°C. The clay fraction (< 2 µm) separated from a clay-rich soil in a hilly area of the Red River basin containing relatively high amounts of kaolinite was tested for its dispersion properties under the presence of the prepared biochars. Surface charge of biochar-soil clay mixtures was determined by polyelectrolyte titration using a particle charge detector, while corresponding colloidal properties of the mixtures were examined by the test tube method. Both, the soil clay fraction and biochar samples showed strongly negative surface charge and their surface charge was variable depending on pH. In a pH range from 3 to 10 and at an electrolyte background of 0.01 M NaCl, surface charge of the clay fraction decreased from -1.68 to -44.75 mmol<sub>c</sub> Kg<sup>-1</sup>, while the biochars surface charge varied from -0.6 to -48.8 mmol<sub>c</sub> Kg<sup>-1</sup>. Soil clays were more strongly dispersed in the presence of biochars by increasing electrostatic repulsive forces. The biochar preparation method had a crucial role for surface charge properties of biochars and in consequence colloidal dynamics of biochar-clay mixtures. The N<sub>2</sub>-supported pyrolysis at lower temperatures does not increase charge density but creates a more porous structure, thereby increasing the total negative net charges. As a result, the N<sub>2</sub>-supported biochars favor clay dispersion more effectively, while the open-pyrolysis biochars showed lesser effects. Our results indicate that fine-sized biochar amendments generally enhance the risk of clay loss, however, such techniques for creating low-charged biochars can help to decrease clay dispersibility when applying biochar for soil.</p>

Shapes of Polyelectrolyte Titration Curves. 2. The Deviant Behavior of Labile Polyelectrolytes

2008 ◽  
Vol 41 (21) ◽  
pp. 8198-8203 ◽  
Author(s):  
Yuguo Cui ◽  
Robert Pelton ◽  
Howard Ketelson
Keyword(s):  
Deviant Behavior ◽  
Titration Curves ◽  
Polyelectrolyte Titration

scholarly journals Explicit Ion Effects on the Charge and Conformation of Weak Polyelectrolytes

Polymers ◽  
2019 ◽  
Vol 11 (1) ◽  
pp. 183 ◽  
Author(s):  
Vikramjit Rathee ◽  
Hythem Sidky ◽  
Benjamin Sikora ◽  
Jonathan Whitmer
Keyword(s):  
Salt Concentration ◽  
New Technologies ◽  
Starting Point ◽  
Comprehensive Picture ◽  
Ionization Behavior ◽  
Ion Effects ◽  
High Concentrations ◽  
Dynamics Simulations ◽  
Polyelectrolyte Titration ◽  
Weak Polyelectrolytes

The titration behavior of weak polyelectrolytes is of high importance, due to their uses in new technologies including nanofiltration and drug delivery applications. A comprehensive picture of polyelectrolyte titration under relevant conditions is currently lacking, due to the complexity of systems involved in the process. One must contend with the inherent structural and solvation properties of the polymer, the presence of counterions, and local chemical equilibria enforced by background salt concentration and solution acidity. Moreover, for these cases, the systems of interest have locally high concentrations of monomers, induced by polymer connectivity or confinement, and thus deviate from ideal titration behavior. This work furthers knowledge in this limit utilizing hybrid Monte Carlo–Molecular Dynamics simulations to investigate the influence of salt concentration, pK a , pH, and counterion valence in determining the coil-to-globule transition of poorly solvated weak polyelectrolytes. We characterize this transition at a range of experimentally relevant salt concentrations and explicitly examine the role multivalent salts play in determining polyelectrolyte ionization behavior and conformations. These simulations serve as an essential starting point in understanding the complexation between weak polyelectrolytes and ion rejection of self-assembled copolymer membranes.

scholarly journals Polyelectrolyte Titration:  Theory and Experiment

2000 ◽  
Vol 104 (47) ◽  
pp. 11027-11034 ◽  
Author(s):  
Itamar Borukhov ◽  
David Andelman ◽  
Regis Borrega ◽  
Michel Cloitre ◽  
Ludwik Leibler ◽  
...  
Keyword(s):  
Polyelectrolyte Titration ◽  
Theory And Experiment
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